全文获取类型
收费全文 | 545篇 |
免费 | 16篇 |
国内免费 | 3篇 |
专业分类
化学 | 263篇 |
晶体学 | 10篇 |
力学 | 8篇 |
数学 | 27篇 |
物理学 | 256篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 14篇 |
2017年 | 7篇 |
2016年 | 13篇 |
2015年 | 9篇 |
2014年 | 18篇 |
2013年 | 48篇 |
2012年 | 23篇 |
2011年 | 35篇 |
2010年 | 16篇 |
2009年 | 24篇 |
2008年 | 24篇 |
2007年 | 23篇 |
2006年 | 20篇 |
2005年 | 22篇 |
2004年 | 12篇 |
2003年 | 8篇 |
2002年 | 18篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 17篇 |
1995年 | 17篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 13篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 14篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 2篇 |
1975年 | 4篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1938年 | 2篇 |
排序方式: 共有564条查询结果,搜索用时 15 毫秒
401.
Bhattacharjee S Marchewka C Welter J Kowalczyk R Wilsen CB Lau YY Booske JH Singh A Scharer JE Gilgenbach RM Neumann MJ Keyser MW 《Physical review letters》2003,90(9):098303
The first observations and measurements are reported on suppression of the third-order intermodulation (IM3) product arising from nonlinear mixing of two drive frequencies in a klystron, by externally injecting a wave at the IM3 product frequency. Optimum amplitude and phase of the injected wave for maximum suppression are examined. Results indicate that suppression of the IM3 product by as much as 30 dB can be achieved. Experimental results compare favorably with predictions of a 1D simulation code that takes into account all kinematical and dynamical effects including charge overtaking and space charge forces. 相似文献
402.
S. Datta J.K. Bhattacharjee 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(2):247-248
A technique used by Edwards and Singh [8] in the study of polymers is used to provide a simple analytic procedure for calculating
the upper bound of the energies of a class of singular potentials. The accuracy of our procedure turns out to be better than
1%.
Received 29 August 2002 / Received in final form 20 November 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: sumita@bose.res.in 相似文献
403.
Abbott B Abolins M Abramov V Acharya BS Adams DL Adams M Alves GA Amos N Anderson EW Baarmand MM Babintsev VV Babukhadia L Baden A Baldin B Balm PW Banerjee S Bantly J Barberis E Baringer P Bartlett JF Bassler U Bean A Begel M Belyaev A Beri SB Bernardi G Bertram I Besson A Bezzubov VA Bhat PC Bhatnagar V Bhattacharjee M Blazey G Blessing S Boehnlein A Bojko NI Borcherding F Brandt A Breedon R Briskin G Brock R Brooijmans G Bross A Buchholz D Buehler M Buescher V Burtovoi VS Butler JM Canelli F 《Physical review letters》2001,86(12):2523-2528
The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory. 相似文献
404.
Longitudinal and transverse waves in Yukawa crystals 总被引:1,自引:0,他引:1
A unified theoretical treatment is given of longitudinal (or compressional) and transverse modes in Yukawa crystals, including the effects of damping. Dispersion relations are obtained for hexagonal lattices in two dimensions and bcc and fcc lattices in three dimensions. Theoretical predictions are compared with two recent experiments. 相似文献
405.
Sinha J Layek S Mandal GC Bhattacharjee M 《Chemical communications (Cambridge, England)》2001,(19):1916-1917
Reaction of alpha,beta-unsaturated aromatic carboxylic acids with KBr and H2O2 in the presence of Na2MoO4.2H2O in aqueous medium affords beta-bromo alkenes in high yield. 相似文献
406.
D. K. Maity P. K. Bandyopadhyay D. K. Bhattacharjee 《Zeitschrift fur Physik C Particles and Fields》1995,65(1):75-78
In this paper we examine the similarity between clan structure and self-similar cascading in high energy proton-nucleus interactions at 70 GeV/c in emulsion. The investigation shows that the negative bionomial fitting parameterk can be used for the evaluation of factorial moments in intermittency studies and that these exhibit similar behaviour with those derived from nonstatistical procedure. The results of our study signify compatibility between clan cascading and self-similar cascading in soft hadroization processes. 相似文献
407.
Raman spectroscopic studies of the liquid crystalline compounds 5O.5 and 5O.6 revealed that the two aromatic rings in the core are in different environments with distorted electron cloud distributions, and the behaviour of each of these rings is independent of the other. Increased chain length results in the development of strain on the molecules. During the SmF-SmB phase transition there is a slight transfer of charge, along with an increase in the freedom of the individual molecules. Our experiments also reveal that the molecules are strained in the crystalline state and adopt some preferred orientations in free-standing films. There is also a tendency towards the elongation of the molecules along the C N linkage in solution for 5O.6. Raman spectra of 5O.6 in free-standing films have shown dramatic changes compared with the spectra recorded in the bulk. 相似文献
408.
Dynamic scaling arguments to derive the exponent for critical slowing down near the Curie point are reviwed. The determinations
of this exponent by neutron scattering, hyperfine interactions and sound attenuation are discussed. The hyperfine interaction
observations are used to make a prediction about the sound attenuation experiments. 相似文献
409.
We construct a quantum mechanical perturbation theory which uses the multiple time scale technique. Working with the time translation operator, we use a variant on the method of Bender and Bettencourt. Our perturbation theory smoothly crosses over to the classical result as Planck's -->0. It is seen that this technique has a nonperturbative element built into it. 相似文献
410.
We study the logistic mapping with the nonlinearity parameter varied through a delayed feedback mechanism. This history dependent modulation through a phaselike variable offers an enhanced possibility for stabilization of periodic dynamics. Study of the system as a function of nonlinearity and modulation parameters reveals new phenomena: In addition to period-doubling and tangent bifurcations, there can be bifurcations where the period increases by unity. These are extensions of crises that arise in nonlinear dynamical systems. Periodic orbits in this system can be systematized via the kneading theory, which in the present case extends the analysis of Metropolis, Stein, and Stein for unimodal maps. 相似文献